1. Field of the Invention
The present invention relates to backerboard that is particularly well suited for use with bullnose tile pieces.
2. Description of Related Art
Backerboard is a composite sheet of a core material with a bonding coating on at least one surface that provides a bonding surface for attaching finishing products or adhesives. U.S. Pat. No. 5,961,900 and U.S. Pat. No. 5,350,544 both describe backerboards and methods of their manufacture.
A major use of backerboards is in combination with tile installation. Backerboards provide a smooth surface for applying tile. Certain backerboards, such as those with a foam core, can also provide thermal and acoustical insulation through a tiled substrate. Installation of backerboard and tile currently can be a laborious and time consuming effort, especially when installing over or into various corners, curbs and wall inserts. A major contributing factor to the labor time is installation of backerboard into corners, curbs and wall inserts.
Current process for forming corners with backerboard produce sharp outside corners, which are not particularly well suited for overlaying with bullnose tiles. Bullnose tile pieces have a curved profile to soften a corner""s radius of curvature. Applying a bullnose tile over a sharp corner can be challenging. If backerboard is present over the entire corner by, for example, butting backerboard pieces to one another then the corner projects a bullnose tile off from the adjoining surfaces of backerboard. As an alternative, installers typically apply backerboard only to the adjoining surfaces without extending over the edge itself. As a result, a gap is present along corner edge, under the curved corner of the bullnose tile. This gap is often filled with adhesive, but can provide a means of water leakage through to a substrate behind the backerboard.
A backerboard that can bend into corner and curb shapes while maintaining a curved outer profile to support bullnose tiles is desirable, particularly if the backerboard remains intact around the corner in order to provide a water barrier.
The present invention is a backerboard comprising opposing surfaces, a bonding coating on at least one surface, and at least one shaped cut or groove that penetrates through and traverses a surface opposing a surface containing a bonding coating but does not penetrate through the bonding coating on the opposing surface; wherein said backerboard can bend along said shaped cut or groove to form an L-shaped corner having a rounded outer edge and a sharp inner edge.
The present invention addresses a need in the art by providing a backerboard that can bend into corner and curb shapes while maintaining a curved outer profile to support bullnose tiles.